Hyperfine spin qubits in irradiated malonic acid: heat-bath algorithmic cooling

Abstract

The ability to perform quantum error correction is a significant hurdle for scalable quantum information processing. A key requirement for multiple-round quantum error correction is the ability to dynamically extract entropy from ancilla qubits. Heat-bath algorithmic cooling is a method that uses quantum logic operations to move entropy from one subsystem to another, and permits cooling of a spin qubit below the closed system (Shannon) bound. Gamma-irradiated, ${}^{13}$C-labeled malonic acid provides up to 5 spin qubits: 1 spin-half electron and 4 spin-half nuclei. The nuclei are strongly hyperfine coupled to the electron and can be controlled either by exploiting the anisotropic part of the hyperfine interaction or by using pulsed electron-nuclear double resonance (ENDOR) techniques. The electron connects the nuclei to a heat-bath with a much colder effective temperature determined by the electron's thermal spin polarization. By accurately determining the full spin Hamiltonian and performing realistic algorithmic simulations, we show that an experimental demonstration of heat-bath algorithmic cooling beyond the Shannon bound is feasible in both 3-qubit and 5-qubit variants of this spin system. Similar techniques could be useful for polarizing nuclei in molecular or crystalline systems that allow for non-equilibrium optical polarization of the electron spin.

arXiv comment25 pages, 13 figures, published in Quantum Information Processing, Springer (2015)

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Cited by in corpus (12)

• Role of vibrations on decoherence in molecular spin qubits: The case of [Cu(mnt)${}_2$]${}^{2-}$
• Heat-Bath Algorithmic Cooling with correlated qubit-environment interactions
• Achievable polarization for Heat-Bath Algorithmic Cooling
• Estimating the coherence of noise in quantum control of a solid-state qubit
• Gradient-based closed-loop quantum optimal control in a solid-state two-qubit system
• Strong Algorithmic Cooling in Large Star-Topology Quantum Registers
• Randomized benchmarking of quantum gates implemented by electron spin resonance
• Thermodynamics of a minimal algorithmic cooling refrigerator
• Thermodynamic Analysis of Algorithmic Cooling Protocols: Efficiency Metrics and Improved Designs
• State-independent robust heat-bath algorithmic cooling of nuclear spins
• Expressivity of deterministic quantum computation with one qubit
• Algorithmic cooling for resolving state preparation and measurement errors in quantum computing